Switching means

ABSTRACT

By means of connectors with pins which shieldedly extend into a cavity defined by a metal housing into which the connectors are fixedly inserted, the inner line of a first coaxial cable is exposed for connection with the inner line of one or the other of the two other coaxial cables. Such alternative connection is accomplished by a pair of magnetizable conductive reeds, each being disposed to bridge, and thereby make contact between, the pin of the first coaxial cable and the pin connected with the inner line of one of the two other cables. Each reed is displaceable in a transverse direction and, upon such displacement, breaks its connections and is grounded against the metal wall of the housing. Such displacement may be effected by the energization of solenoid coils disposed perpendicularly to a first reed, thereby creating a magnetic field to draw that reed toward the coils and against the housing wall. Each reed is attached to one side of a rocker assembly which is spring-biased against the first reed to dispose it in its connecting position when its solenoid coils are not energized. Such disposition of the first reed, through its attachment to the rocker assembly, secures the other reed in its disconnecting and grounded position, but the reed positions are reversed when the solenoid coils are energized. A control switch is provided to enable an operator selectively to cause energization of the coils or to deenergize them. An indicator circuit may be provided to indicate which reed is in its bridging and hence, connecting position.

United States Patent Brastow et al.

[ 1 Sept. 5, 1972 [54] SWITCHING MEANS [72] Inventors: Edgar R. Brastow, Cerritos; Tai Y.

Lee, Los Angeles, both of Calif.

[73] Assignee: Transco Producm, lnc., Venice,

- Calif.

Y [22] Filed: Jan. 28, 1971 21 App1.No.: 110,712

[52] US. Cl. ..335/5, 333/7 [51] Int. Cl. ..H01h 53/00 [58] Field of Search ..335/5, 4; 200/153 S; 333/7, 333/97 S [56] References Cited UNITED STATES PATENTS 2,498,907 2/1950 Atwood et al. ..33 5/5 2,584,901 2/ 1952 Miller et al. ..200/ 153 S 3,414,849 12/1968 Burt, Jr ..333/97 S Primary Examiner-Harold Broome Attorney-Smyth, Roston & Pavitt [57] ABSTRACT By means of connectors with pins which shieldedly extend into, a cavity defined by a metal housing into which the connectors are fixedly inserted, the inner line of a first coaxial cable is exposed for connection with the inner line of one or the other of the two other coaxial cables. Such alternative connection is accomplished by a pair of magnetizable conductive reeds, each being disposed to bridge, and thereby make contact between, the pin of the first coaxial cable and the pin connected with the inner line of one of the two other cables. Each reed is displaceable in a transverse direction and, upon such displacement, breaks its connections and is grounded against the metal wall of the housing. Such displacement may be efiected by the energization of solenoid coils disposed perpendicularly to a first reed, thereby creating a magnetic field to draw that reed toward the coils and against the housing wall. Each reed is attached to one side of a rocker assembly which is spring-biased against the first reed to dispose it in its connecting position when its solenoid coils are not energized. Such disposition of the first reed, through its attachment to the rocker assembly, secures the other reed in its disconnecting and grounded position, but the reed positions are reversed when the solenoid coils are energized. A control switch is provided to enable an operator selectively to cause energization of the coils or to de-energize them. An indicator circuit may be provided to indicate which reed is in its bridging and hence, connecting position. 7

21 Claims, 5 Drawing Figures BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to switches of the type which are particularly adapted for miniaturization and for effecting connections between a first co-axial cable and one or the other of two more coaxial cables over which microwave signals are being carried.

2. Description of the Prior Art The switching of coaxial cable transmission lines, particularly where such lines carry currents at the higher. end of the frequency spectrum, has long presented special problems towards the solutions of which electronic engineers have devoted considerable attention and effort. Examples of solutions proposed for certain specific applications in this area are found in the following United States Pat; Concelman, No. 2,958,053; Scholefield, No. 3,087,125; Concelman, No. 3,088,081.

As pointed out in the specifications of these patents, the switching of the lines of coaxial cables requires special switch body constructions to eliminate or to attenuate as much as possible, cross-talk which arises from one or the other of the exposed center lines of the coaxial cables involved. Particularly where the cables are carrying microwave transmissions, it is desirable to miniaturize the switches and to have them operated at relatively low power levels. However, the switches must be completely responsive to control signals. Energy reflections must be kept at a minimum.

In addition to the problems and requirements described in the patents listed above, it is also desirable that the switch be resistant to vibration. For example, when its contacting element is moved to a selected position, it should remain there in firm contact with the points it is to connect. When it is moved out of such contact, it should remain completely so untili' it is brought back into contact by a control signal. Fuither, where the switch may be exposed to the elements, it should be of a design whereby the movable elements and contacts are sealed within the housing. Also desirable is the provision of indicator circuits whereby the position of the switching elements at any instant may be accurately determined. The switch should also'have a failsafe position to which it is automatically moved in the event of a power failure.

However, in addition to meeting all such requirements, the switch should be of a design which can be fabricated for the lowest possible cost and rapidly on a mass production basis.

Prior art switches do not appear to have accomplished all of these objectives.

SUMMARY OF THE INVENTION The disclosed embodiment of the present invention is constructed of a die-cast aluminum housing which defines a cavity with an open top closeable by a cover plate after assembly of the switching elements within the cavity. One side wall of the housing receives a pair of solenoid coils disposed side-by-side but with their axes projecting into the cavity. Another wall of the housing is orificed to receive and have threadedly inserted therein, in spaced side-by-side relationship, three coaxial cable connectors to each of which a coaxial cable is attached from the outside. The inner line of each cable is connected to a pin which extends into a shielded area of the cavity and becomes a contact point. The inner line of the main cable, which is to be 'switched to one of the other two cables, is connected to the center one of three pins disposed in alignment within the shielded areas of the cavity. Each inner line of the other two cables is connected to one of the other two pins, the ends of which serve as contact points. A pair of reeds, at least one of which is magnetizable, is so mounted within the cavity that each reed is movable between a first position in whichit bridges and connects one of the outer contact points and the center contact point, and a second position in which the reed is moved away from the contact points and against the cavity wall to ground itself. The magnetizable reed is further disposed in such a manner as to lie within, and be attracted to, the magnetic field of a pair of solenoid coils when the latter are energized. Thereby such energization displaces the magnetizable reed from its first position to its second position.

To effect a positive latching action, the two reeds are attached to the opposite ends of a rocker arm which is spring-biased into a position whereby the magnetizable reed is maintained in its first position, and the other reed, in its second position, and the other reed, in its second position. The force of the spring, however, is not sufficient to prevent the displacement of the magnetizable reed which is in its first position when the solenoid coils within the magnetic field of which such reed is disposed, is energized. Upon such energization of the solenoid coils, the magnetizable reed is drawn away from the contact points which it bridgesto its second and grounded position, and simultaneously acts on the rocker arm to move the other reed into its first position, thereby making connection between the two contact points which the other reed serves to bridge. To switch back to the opposite positions of the two reeds, the solenoid coils are simply de-energized. This results in the spring forcing the magnetizable reed back to its first position and through the rocker arm, the other reed is shifted back into its second position.

If desired, indicator circuitry may be built into the assembly and operated by a single-pole double-throw switch'tied in with the movement of the rocker arm.

The cover plate may be secured to the cast housing by screws or otherwise, with a gasket preferably being interposed between the housing and cover plate to seal the moving and contacting parts against contamination from outside elements.

The entire unit may be mounted by means of stamped clamps.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings,

FIG. 1 is a plan view, partly broken away.

FIG. 2 is a sectional view taken in the direction of the arrows and on the line 2--2 of FIG. 1.

FIG. 3 is an enlarged detail of the rocker arm and reed assembly which operates to make contact with the alternative pairs of pins.

FIG. 4 is an enlarged detail showing the manner in which the reeds are attached to the rocker arm plunger.

FIG. 5 is schematic circuit diagram of the switching unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS For a better understanding of the present invention, FIG. 5 should first be considered for an appreciation of what the illustrated embodiment of the invention is intended to accomplish. The purpose is to effect a switching of coaxial cable to one or the other of the alternate coaxial cables 12, /4. Since the outer or shielding lines '16 of these cables are normally grounded, the only switching which need be accomplished is that of the inner line 10a of cable 10 to the inner line 120 or inner line 14a of either cable 12 or 14 respectively. However, particularly in the microwave range of the frequency spectrum, the inner line 10a may be highly radiative with the result that unless it, the switching devices and the inner line of the cable to which it is switched, are properly ground-shielded, undesirable signal leakage to the inner line of the other coaxial cable to which switching is not effected, may result. In some instances such leakage could cause improper control signals being emitted to, or picked up by, very costly equipment or apparatus the functioning and even existence of which is dependent upon receipt of proper control signals.

Turning to FIGS. 1 and 2, it may be seen that the three cables,-10, 12 and 14 are brought into the base 180 of a metal housing 18 through standard coaxial connectors 20, 20a and 20b which are inserted in orifices 21, 21a and 21b disposed in a straight line and equidistantly separated from each other in the housing base 18a. The housing itself may be constructed of two parts, a cast metal base 180 and a cover 18b. The metal base 18a includes an upwardly projecting block 180. Each connector 20, 20a and 20b comprises an outer cylinder-nut assembly 22 which receives and holds the outer shield 16 of the cable 10, 12 or 14, the end of which is plugged into the connectors 20, 20a, 20b, and is grounded by its contact with the cast metal base 18a of the housing 18. Disposed coaxially within and insulated from each cylinder-nut assembly 22 is one of the pins 24, 24a or 24b, each of which projects beyond the inner end of its respective cylinder-nut assembly. The cast metal base 18a is formed internally with three cylindrical bores 26, 26a, 26b, which extend through the projecting block 180 and each of which bores is coaxial with one of the orifices 21, 21a or 21b and is of a sufficiently greater diameter than that of the pins 24, 24a, 24b, to permit one of the pins to project coaxially therewithin and without contacting the inner wall defining the bore 26, 26a or 26b. These bores are connected by a slot 28 in the block, 180 FIG. 1), which slot 28 extends between quadrants 28a, 28d of the outer bores 26, 26b and passes into the nearest quadrant 28b, 28c respectively of the center bore 26a. As may be seen in FIG. 2, the depth of the slot 28 is sufficient to expose the ends 30, 30a, 30b of each of the pins 24, 24a, 24b respectively.

Connection is effected between pin 24a and altematively one or the other of pins 24 and 24b by providing a pair of conductive reeds 32, 32: each of which is displaceable in a direction transverse to the axes of the pins Al reed 32 is displaceable from a first position in contact with the ends 30 and 30a of pins 24 and 24a respectively to a second position wherein such contact is completely broken and the reed is grounded against the wall 34 of the block 180 which defines one side of the slot 28. Similarly the reed 32a is displaceable from a first position in contact with the ends 30a and 30b of the pins 24a and 24b respectively to a second position wherein such contact is completely broken and the reed 32a is grounded against said wall 34.

The displacement of the reeds 32, 32a in such a manner that when reed 32 is in its first position, reed 32a is in its second position, and vice-versa, is accomplished by mounting one reed on each side of the rocker assembly 36 as A2 illustrated in detail, in FIG. 3 by fabricating reed 32 of magnetizable material and by providing a pair of electromagnets 38, 38a in the wall 34 of the block 18c. Each of the electromagnets 38, 38a is disposed in proximity to a difficult end of the reed 32 and disposed in alignment with the direction which the reed 32 is intended to travel. Coils 39, 39a to energize the electromagnets 38, 38a respectively may be disposed outside the side wall 34a of the block 18c.

The rocker assembly 36 is comprised of an arm 40 which is disposed outside that portion of the cast metal base 18a which projects upwardly to define the bores 26, 26a and 26b and slot 28, and a rotatable fulcrum shaft 42 with which the arm 40 rocks or see-saws. Each end 40a, 40b of the arm 40 is bi-furcated to receive a pin, 44 or 44a, projecting laterally from the head 46, 46a of a plastic or hard rubber plunger 48 or 48a respectively. The block 180 is further bored transversely at 50, 50a to receive the plungers 48, 48a respectively and is further bored at 52, 52a, 52b and 52c to form pockets to receive the ends of a series of short plastic guide elements 54, 54a, 54b and 54c respectively.

Each plunger 48, 48a is formed as shown in FIG. 4 to provide a notch 56 with a detent means such as rectangular piece 58 extending diametrically across the notch 56. By providing the reed 32 or 32a with a detent means such as slot 60, the latter may be fitted into the notch 56 so that the reed 32 and plunger 48 move as an integral unit. The series of teflon or other plastic guide elements 54, 54a, 54b and 54c are laid across the upper exposed edges of the reeds 32, 32a respectively, and may travel with the reeds between opposed sets of pockets 52, 52a, 52b, 52c, in the wall of the block 18c.

A helical compression spring 64 is provided around the upper end of the plunger 48 and extends a short distance into a counterbore 66 in the side wall 68 of the metal block 180 where it seats against the bottom 70 of the counterbore. The upper end of the spring presses against the underside 72 of the head 46 of the plunger 48.

An adhesive aluminum tape 73 is placed over and adhered to the top wall 74 of the metal block 18c, thereby not only shielding the two reeds 32, 32a and the pins 24, 24a, 24b, but also effectively hermetically sealing them in the block 18c, particularly if the electromagnets 38, 38a, the plungers 48, 48a and the pins 24, 24a and 24b are all properly gasketed in the areas where they, enter or pass through the slot 28 or bores 26, 26a or 26b.

In order to energize the coils 39, 39a when desired wires 76 extend from the coils to control switched 78 mounted in the housing cover 18b and to a terminal board not shown), to which a source of voltage is connected.

In operation the switch is normally maintained by the compression spring 64 with the reed 32 in its first position, namely, making contact between pins 24 and 24a, and with the reed 32a in its second position, namely out of contact with pins 24a and 24b and grounded. In this positioning, the inner line a of cable 10 is switched to the inner line 12a of cable 12, and is maintained in that position desirably the failsafe position) until the solenoid coils 39, 39a are energized by the pressing of the switches 78 by the operator. When this is done, the coils develop magnetic fields about the electromagnets 38, 38a which thereupon pull the reed 32 downwardly in FIG. 1), despite the opposing force exerted by the spring 64, to break contact with the pins 24, 24a and ground the reed 32 against the inner wall 34 of the metal block 18c. Simultaneously, the downward movement of the reed 32 draws with it the plunger 48 which, in turn, pulls the left side of the rocker arm 40 downwardly to rotate the fulcrum shaft 42 and lift the right side of the arm 40 and plunger 48a to bring the reed 32a into its first position, where it makes contact with pins 24a and 24b. Thereby the signal on line 10a is shifted from line 12a to line 14a. This position is maintained until the current passing into the coils 39, 39a is terminated, whereupon the compression spring 64 takes over and forces the plunger 48 and reed 32 upwardly to dispose the latter in its first and contacting position.

Although it is not necessary to successful operation of the switching means hereinabove described and illustrated in the accompanyingdrawings, desirably an indicator circuit could be incorporated as shown schematically in FIG. 5. In the embodiment there shown an indicator switch 80is attached to the plunger 48 to move up and down therewith between two contacts 82 and 82a. The latter would lead to some visible or other means 84 to indicate whether the coaxial switch was in its first or second position, and this indication would be disclosed by providing a small source of voltage for the indicators, one lead 86 of which would be brought through the indicator switch 80, as illustrated in FIG. 5.

We claim:

1. In combination for introducing a signal from at least one of a set of signal carrying conductors including a first conductor to at least one of a set of signal receiving conductors including second and third conductors in accordance with the input of an electrical signal, comprising:

a housing; I t,

first means electrically connected to each of the conductors for introducing the signal carrying conductors and the signal receiving conductors into the housing;

second means having magnetizable characteristics and movable between first and second positions and having characteristics for moving to the first position to electrically connect the first conductor and the second conductor to thereby introduce the signal from the first conductor to the second conductor and having further characteristics for disengaging the first and second conductors and moving to the second position in electrical contact with the housing in accordance with the magnetization of the second means;

third means for biasing the second means to a particular one of thefirst and second positions; and

fourth means having characteristics for overriding the third means and for magnetically activating the second means in response to the electrical signal input to obtain a movement of the second means to the other one of the first and second positions.

2. The switching means as defined in claim 1 further comprising:

fifth means movable between first and second positions and having characteristics for moving to the first position to electrically connect the first conductor and the third conductor to thereby introduce the signal from the first conductor to the third conductor and having further characteristics for disengaging the first and third conductors and moving to the second position in electrical contact with the housing; and

sixth means mechanically coupling the second means and the fifth means so that when the second means is in one of the first and second positions the fifth means is in the other of the first and second positions whereby the signal on the first conductor is alternatively introduced to the second and third conductors.

3. The switching means as recited in claim 2 wherein the fourth means comprises at least one electromagnet in proximity to the second means for receiving the electrical input and in response thereto generating a magnetic field magnetizing the second means to displace the second means to the other one of its first and second positions whereby the fifth means is displaced by the sixth means to the position opposite to that of the second means.

4. The switching means as defined in claim 2 wherein the sixth means comprises:

first and second plungers having insulating characteristics and mechanically connected to the second means and the fifth means respectively;

a crossarm pivotable upon a fulcrum and slidingly engaging the unconnected ends of the first and second plungers on opposite sides of the fulcrum so that the crossarrn displaces the fifth means to its particular position as the second means is displaced to its other position by the fourth means, and the crossarrn displaces the fifth means to its other position as the second means is biased to its particular position by the third means respectively.

5. The combination as defined in claim 4 further comprising:

first detent means included in one of the first plunger and the second means;

portions of the other of the first plunger and the second means defining second detent means;

the first detent means registered with the second detent means so that the second means is restricted to movement in a first direction; and

eighth means having insulating characteristics and disposed in fixed relationship with the housing for slidingly engaging the second means to resist the movement of the second means in the first direction.

6. The combination as recited in claim 5 wherein the eighth means comprises:

at least one pin disposed in contact with the housing substantially parallel to the first plunger and slidingly engaging the second means so that movement of the second means in the first direction is accompanied by movement of the pin from contact with the housing; and

ninth means for retaining the pin in contact with the housing so that movement of the second means in the first direction is inhibited.

7. The combination recited in claim 2 wherein the fourth means is disposed on the side of the second means opposite to that of the sixth means.

8. A switching means for receiving a plurality of conductors including a first conductor having an electrical signal input impressed thereon and second and third conductors for alternately receiving the signal from the first conductor in accordance with the operation of the switching means in first and second modes, including:

a housing having first portions which define a slot in an interior surface of the housing and second portions defining a plurality of holed extending through the housing into the slot;

first means extending through the holes into the slot and respectively connected to the conductors to provide within the housing contacts for introducing the signal individually to the second and third conductors;

second means disposed between, the first means and the housing for electrically insulating the first means from the housing and hermetrically sealing the holes with the first means extending therethrough;

third means movable between first and second positions and movable to the first position to establish electrical continuity between the first and second conductors when the switching means is in the first mode of operation and movable to the second an electrically conductive foil included in the tape and in electrical contact with the housing so that a reference potential encompasses the third and fourth means to insulate the conductors from signals extraneous to the conductors.

ill. The switching means as recited in claim 8 further comprising:

seventh means connected to the housing and encasing the first means, third means and fourth means to insulate the conductors from extraneous signals. 12. Switching means as defined in claim 11 further comprising:

wherein the fifth means comprises a spring biased in an position to contact the housing when the switching means is in the second mode of operation;

fourth means having characteristics for establishing electrical continuity between the first and third conductors when the switching means is in the second mode of operation and contacting the housing when the switching means is in the first mode of operation;

the third means having magnetizable properties to control the movement of the third means between the first and second positions;

fifth means for biasing the third means to a particular one of the first and second positions; and

sixth means responsive to the electrical signal input for magnetiaing the third means to obtain a displacement of the third means to the other one of the first and second positions.

9. The switching means as recited in claim 8 wherein the housing includes third portions defining depressions in the interior surface which are aligned transversely across the slot, the switching means further comprising;

seventh means disposed within the depressions to insulate the third means and the fourth means from the housing when the switching means is in the second mode and the first mode of operation respectively.

10. The switching means as recited in claim 9 further comprising:

a tape disposed over the slot and adhered to the interior surface of the housing for maintaining the seventh means in the depression and herrnetrically sealing the slot, and

open position and disposed about the first plunger between the housing and the crossarm and the sixth means comprises at least one electromagnet disposed on the side of the third means opposite to that of the first plunger and forming a magnetic circuit with the third means.

14. In combination for introducing at least one signal among a plurality of conductors in accordance with first and second modes of operation, comprising:

a housing with a first portion defining holes in the walls of the housing;

each of the conductors passing through one of the holes into the housing wherein at least a first one of the conductors has a signal impressed thereupon to be switched alternatively between at least a second one and a third one of the conductors;

first means for establishing electrical continuity between the first and second conductors when the switching means is in the first mode of operation and interrupting electrical continuity between the first and second conductors when the switching means is in the second mode of operation;

second means for establishing electrical continuity between the first and third conductors when the switching means is in the second mode of operation and interrupting electrical continuity between the first and third conductors when the second means is in the first mode of operation;

third means connecting the first means and the second means so that the movement of the first means controls the movement of the second means;

fourth means forming a magnetic circuit with the first means displaced to place the switching means in one of the first and second modes of operation; whereby the signal on the first conductor is switched to the second conductor when the switching means is in the first mode of operation and the signal on the first conductor is switched to the third conductor when the switching means is in the second mode of operation.

15. The switching means as defined in claim 14 further comprising:

first and second plungers connected to and extending longitudinally in the direction of movement of the first means and second means respectively;

a crossarm pivotable upon a fulcrum and slidingly engaging the unconnected ends of the first and second plungers on opposite sides of the fulcrum so that the first means and second means move in opposite directions within the housing.

16. The switching means as defined in claim 15 wherein the switching means further comprises:

a central region included in the crossarm;

first and second end regions of the crossarm each shaped to form a fork having a pair of elements facing outwardly of the central region wherein the elements of each of the forks are spaced a particular distance;

an arm included in each of the first and second plungers extending between a respective pair of the elements in the first and second end regions of the crossarm;

each of the arms having a dimension less than the particular distance in a direction transverse to the respective elements of the forks so that the resistance to movement of the arms between the respective elements is decreased and the play between each of the arms and the respective elements is increased; and

a shaft mounted on the housing and pivotally engaging the central region of the crossarm closer to the first plunger than to the second plunger;

whereby the second end region of the crossarm moves a greater distance than the first end region to compensate for the play between the arms of the plungers and the respective elements of the forks.

17. Improved switching means, said means being particularly adapted for miniaturization and to effect the switching of the inner line of a first coaxial cable between the inner line of a second coaxial cable and that of a third such cable, said switching means comprising:

a metallic housing, said housing defining a cavity and having openings through said housing into the cavity, one opening for each said cable whereby the inner line of each said cable may be introduced into said cavity in an insulated manner and exposed therein for electrical connection with an element,

comprehending three pin-like elements insulated from the housing a first one of said elements being connected electrically to the inner line of the first said cable, and each of the other two elements being connected electrically to the inner line of the second or third cables, one end of each of said elements serving as a contact point; and providing at least partial shielding for the exposed inner line of each said cable and each said element connected thereto, from the inner line of each of the other said cable and the element connected respectively thereto;

a pair of conductive reeds, at least one of said reeds being of magnetizable material, each of said reeds being disposed to bridge and electrically connect the contact point of the first element and the contact point of one of the other two elements;

means to dispose each of said conductive reeds so that it may be displaced from a first position in which it bridges and connects the two contact points which it is so adapted to bridge and electrically connect, to a second position in which it is out of contact with both of said contact points and is grounded against the wall of the metallic housmg;

electromagnetic means, said means being so disposed and connectable to a source of voltage that, when the voltage is applied to such electromagnetic means, it creates a magnetic field embracing the magnetizable reed to displace it from its first position to its second position;

a rocker arm assembly, said assembly including an arm and a fulcrum disposed intermediate the extremities of the arm and about which fulcrum the arm rocks or seesaws, said assembly being so disposed that one end of said arm is mechanically attached to the magnetizable reed, and the other end of the arm is mechanically attached to the other reed, whereby when said arm is disposed in a first position, the magnetizable reed attached to one end thereof is disposed in its first position and the other reed attached to the other end of the arm is disposed in its second position, and conversely, when said arm is rocket from its first position into a second position;

plunger means connected to and extending from one end of the rocker arm slideably through one side wall defining the cavity and into a pocket provided in the opposite side wall, each said plunger means engaging the reed in the area of the slotting, whereby the reed and plunger move cojointly with the extremity of the rocker am to which the one end of the plunger is connected;

spring means associated with at least one end of said arm and urging it against movement into its second position, said spring means, however, providing an insufficient urging force to prevent the magnetizable reed from being displaced to its second position by the energization of said electromagnetic means; and

an electrical switch, said switch being connected selectively to apply voltage from said voltage source to said electromagnetic means to energize the same.

18. Improved switching means, said means being particularly adapted for miniaturization and to effect the switching of the inner line of a first coaxial cable between the inner line of a second coaxial cable and the inner line of a third such cable, said switching means comprising:

a metallic housing, said housing defining a cavity, and openings through said housing into the cavity, one of said openings for each of said cables whereby the inner line of each of said cables may be introduced into said cavity in an insulated manner and exposed therein for electrical connection with an inner line of another of said cables;

a plurality of pin-like elements insulated from the housing and including a first element connected electrically to the inner line of the first cable, and a second and third element connected electrically to the inner line of the second and third cables respectively, one end of each of said elements serving as a contact point and providing at least partial shielding for the exposed inner line of each of said cables and each of said elements connected thereto from the inner line of each of the other of said cables and the elements connected respectively thereto;

a pair of conductive reeds, at least one of said reeds being of magnetizable material, one of said reeds being disposed to bridge and electrically connect the contact points of the first element and the second element, and the other of said reeds being disposed to bridge and electrically connect the contact points of the first element and the third element;

means for disposing each of said conductive reeds so that it may be displaced from a first position in which it bridges and electrically connects the two contact points which it is so adapted to bridge and electrically connect, to asecond position in which it is out of contact with both of said contact points and is grounded against the wall of the metallic housing;

electromagnetic means, responsive to an input signal for creating a magnetic field embracing the magnetizable reed to displace it from its first position to its second position;

a rocker arm assembly, said assembly including an arm and a fulcrum disposed intermediate the extremities of the arm and about which fulcrum the arm pivots, said assembly being so disposed that one end of said arm is mechanically attached to the other reed, whereby when said arm is disposed in a first position, the magnetizable reed attached to one end thereof is disposed in its first position 35 and the other reed attached to the other end of the arm is disposed in its second position, and conversely, when said arm is rocked from its first position into a second position;

spring means associated with at least one end of said arm and urging it against movement into its second position, said spring means, however, providing an insufficient urging force to prevent the magnetizable reed from being displaced to its second position by the energization of said electromagnetic means; and

an electrical switch, said switch being connected selectively to apply voltage from said voltage source to said electromagnetic means to energize the same.

19. The switching means as described in claim 18 including an indicator circuit comprising:

indicating means visible outside the housing to disclose whether said rocker arm is disposed in its first or second position,

an actuating arm connected to the indicating means and movable with the rocker arm to actuate the indicating means in accordance with the positioning of said arm.

20. The switching means as described in claim 18, wherein before either reed is moved into its first position, the other reed is first removed from its first position, thereby providing a break-before-make switching action.

21. The switching means described in claim 18,

whereint e cavi t 'n the etal ic housi i covere b a sheet 0 electri aily COIIIIAUCIIJVG tape Ra wing an a he sive surface, which surface is pressed into contact with the top of the housing walls defining the cavity. 

1. In combination for introducing a signal from at least one of a set of signal carrying conductors including a first conductor to at least one of a set of signal receiving conductors including second and third conductors in accordance with the input of an electrical signal, comprising: a housing; first means electrically connected to each of the conductors for introducing the signal carrying conductors and the signal receiving conductors into the housing; second means having magnetizable characteristics and movable between first and second positions and having characteristics for moving to the first position to electrically connect the first conductor and the second conductor to thereby introduce the signal from the first conductor to the second conductor and having further characteristics for disengaging the first and second conductors and moving to the second position in electrical contact with the housing in accordance with the magnetization of the second means; third means for biasing the second means to a particular one of the first and second positions; and fourth means having characteristics for overriding the third means and for magnetically activating the second means in response to the electrical signal input to obtain a movement of the second means to the other one of the first and second positions.
 2. The switching means as defined in claim 1 further comprising: fifth means movable between first and second positions and having characteristics for moving to the first position to electrically connect the first conductor and the third conductor to thereby introduce the signal from the first conductor to the third conductor and having further characteristics for disengaging the first and third conductors and moving to the second position in electrical contact with the housing; and sixth mEans mechanically coupling the second means and the fifth means so that when the second means is in one of the first and second positions the fifth means is in the other of the first and second positions whereby the signal on the first conductor is alternatively introduced to the second and third conductors.
 3. The switching means as recited in claim 2 wherein the fourth means comprises at least one electromagnet in proximity to the second means for receiving the electrical input and in response thereto generating a magnetic field magnetizing the second means to displace the second means to the other one of its first and second positions whereby the fifth means is displaced by the sixth means to the position opposite to that of the second means.
 4. The switching means as defined in claim 2 wherein the sixth means comprises: first and second plungers having insulating characteristics and mechanically connected to the second means and the fifth means respectively; a crossarm pivotable upon a fulcrum and slidingly engaging the unconnected ends of the first and second plungers on opposite sides of the fulcrum so that the crossarm displaces the fifth means to its particular position as the second means is displaced to its other position by the fourth means, and the crossarm displaces the fifth means to its other position as the second means is biased to its particular position by the third means respectively.
 5. The combination as defined in claim 4 further comprising: first detent means included in one of the first plunger and the second means; portions of the other of the first plunger and the second means defining second detent means; the first detent means registered with the second detent means so that the second means is restricted to movement in a first direction; and eighth means having insulating characteristics and disposed in fixed relationship with the housing for slidingly engaging the second means to resist the movement of the second means in the first direction.
 6. The combination as recited in claim 5 wherein the eighth means comprises: at least one pin disposed in contact with the housing substantially parallel to the first plunger and slidingly engaging the second means so that movement of the second means in the first direction is accompanied by movement of the pin from contact with the housing; and ninth means for retaining the pin in contact with the housing so that movement of the second means in the first direction is inhibited.
 7. The combination recited in claim 2 wherein the fourth means is disposed on the side of the second means opposite to that of the sixth means.
 8. A switching means for receiving a plurality of conductors including a first conductor having an electrical signal input impressed thereon and second and third conductors for alternately receiving the signal from the first conductor in accordance with the operation of the switching means in first and second modes, including: a housing having first portions which define a slot in an interior surface of the housing and second portions defining a plurality of holed extending through the housing into the slot; first means extending through the holes into the slot and respectively connected to the conductors to provide within the housing contacts for introducing the signal individually to the second and third conductors; second means disposed between the first means and the housing for electrically insulating the first means from the housing and hermetrically sealing the holes with the first means extending therethrough; third means movable between first and second positions and movable to the first position to establish electrical continuity between the first and second conductors when the switching means is in the first mode of operation and movable to the second position to contact the housing when the switching means is in the second mode of operation; fourth means having characteristics for establishing electrical Continuity between the first and third conductors when the switching means is in the second mode of operation and contacting the housing when the switching means is in the first mode of operation; the third means having magnetizable properties to control the movement of the third means between the first and second positions; fifth means for biasing the third means to a particular one of the first and second positions; and sixth means responsive to the electrical signal input for magnetizing the third means to obtain a displacement of the third means to the other one of the first and second positions.
 9. The switching means as recited in claim 8 wherein the housing includes third portions defining depressions in the interior surface which are aligned transversely across the slot, the switching means further comprising; seventh means disposed within the depressions to insulate the third means and the fourth means from the housing when the switching means is in the second mode and the first mode of operation respectively.
 10. The switching means as recited in claim 9 further comprising: a tape disposed over the slot and adhered to the interior surface of the housing for maintaining the seventh means in the depression and hermetrically sealing the slot, and an electrically conductive foil included in the tape and in electrical contact with the housing so that a reference potential encompasses the third and fourth means to insulate the conductors from signals extraneous to the conductors.
 11. The switching means as recited in claim 8 further comprising: seventh means connected to the housing and encasing the first means, third means and fourth means to insulate the conductors from extraneous signals.
 12. Switching means as defined in claim 11 further comprising: first and second plungers having insulating characteristics connected to and extending longitudinally in the direction of movement of the third means and fourth means respectively; and a crossarm pivotable upon a fulcrum and slidingly engaging the unconnected ends of the plungers on opposite sides of the fulcrum so that the third means and fourth means move in opposite directions when the modes of operation of the switching means are changed by the fifth means and sixth means.
 13. The switching means as recited in claim 12 wherein the fifth means comprises a spring biased in an open position and disposed about the first plunger between the housing and the crossarm and the sixth means comprises at least one electromagnet disposed on the side of the third means opposite to that of the first plunger and forming a magnetic circuit with the third means.
 14. In combination for introducing at least one signal among a plurality of conductors in accordance with first and second modes of operation, comprising: a housing with a first portion defining holes in the walls of the housing; each of the conductors passing through one of the holes into the housing wherein at least a first one of the conductors has a signal impressed thereupon to be switched alternatively between at least a second one and a third one of the conductors; first means for establishing electrical continuity between the first and second conductors when the switching means is in the first mode of operation and interrupting electrical continuity between the first and second conductors when the switching means is in the second mode of operation; second means for establishing electrical continuity between the first and third conductors when the switching means is in the second mode of operation and interrupting electrical continuity between the first and third conductors when the second means is in the first mode of operation; third means connecting the first means and the second means so that the movement of the first means controls the movement of the second means; fourth means forming a magnetic circuit with the first means displaced to place the switching means in one of tHe first and second modes of operation; whereby the signal on the first conductor is switched to the second conductor when the switching means is in the first mode of operation and the signal on the first conductor is switched to the third conductor when the switching means is in the second mode of operation.
 15. The switching means as defined in claim 14 further comprising: first and second plungers connected to and extending longitudinally in the direction of movement of the first means and second means respectively; a crossarm pivotable upon a fulcrum and slidingly engaging the unconnected ends of the first and second plungers on opposite sides of the fulcrum so that the first means and second means move in opposite directions within the housing.
 16. The switching means as defined in claim 15 wherein the switching means further comprises: a central region included in the crossarm; first and second end regions of the crossarm each shaped to form a fork having a pair of elements facing outwardly of the central region wherein the elements of each of the forks are spaced a particular distance; an arm included in each of the first and second plungers extending between a respective pair of the elements in the first and second end regions of the crossarm; each of the arms having a dimension less than the particular distance in a direction transverse to the respective elements of the forks so that the resistance to movement of the arms between the respective elements is decreased and the play between each of the arms and the respective elements is increased; and a shaft mounted on the housing and pivotally engaging the central region of the crossarm closer to the first plunger than to the second plunger; whereby the second end region of the crossarm moves a greater distance than the first end region to compensate for the play between the arms of the plungers and the respective elements of the forks.
 17. Improved switching means, said means being particularly adapted for miniaturization and to effect the switching of the inner line of a first coaxial cable between the inner line of a second coaxial cable and that of a third such cable, said switching means comprising: a metallic housing, said housing defining a cavity and having openings through said housing into the cavity, one opening for each said cable whereby the inner line of each said cable may be introduced into said cavity in an insulated manner and exposed therein for electrical connection with an element, comprehending three pin-like elements insulated from the housing a first one of said elements being connected electrically to the inner line of the first said cable, and each of the other two elements being connected electrically to the inner line of the second or third cables, one end of each of said elements serving as a contact point; and providing at least partial shielding for the exposed inner line of each said cable and each said element connected thereto, from the inner line of each of the other said cable and the element connected respectively thereto; a pair of conductive reeds, at least one of said reeds being of magnetizable material, each of said reeds being disposed to bridge and electrically connect the contact point of the first element and the contact point of one of the other two elements; means to dispose each of said conductive reeds so that it may be displaced from a first position in which it bridges and connects the two contact points which it is so adapted to bridge and electrically connect, to a second position in which it is out of contact with both of said contact points and is grounded against the wall of the metallic housing; electromagnetic means, said means being so disposed and connectable to a source of voltage that, when the voltage is applied to such electromagnetic means, it creates a magnetic field embracing the magnetizable reed to displace it from its first position to its second position; a rocker arm assembly, said assembly including an arm and a fulcrum disposed intermediate the extremities of the arm and about which fulcrum the arm rocks or seesaws, said assembly being so disposed that one end of said arm is mechanically attached to the magnetizable reed, and the other end of the arm is mechanically attached to the other reed, whereby when said arm is disposed in a first position, the magnetizable reed attached to one end thereof is disposed in its first position and the other reed attached to the other end of the arm is disposed in its second position, and conversely, when said arm is rocket from its first position into a second position; plunger means connected to and extending from one end of the rocker arm slideably through one side wall defining the cavity and into a pocket provided in the opposite side wall, each said plunger means engaging the reed in the area of the slotting, whereby the reed and plunger move cojointly with the extremity of the rocker arm to which the one end of the plunger is connected; spring means associated with at least one end of said arm and urging it against movement into its second position, said spring means, however, providing an insufficient urging force to prevent the magnetizable reed from being displaced to its second position by the energization of said electromagnetic means; and an electrical switch, said switch being connected selectively to apply voltage from said voltage source to said electromagnetic means to energize the same.
 18. Improved switching means, said means being particularly adapted for miniaturization and to effect the switching of the inner line of a first coaxial cable between the inner line of a second coaxial cable and the inner line of a third such cable, said switching means comprising: a metallic housing, said housing defining a cavity, and openings through said housing into the cavity, one of said openings for each of said cables whereby the inner line of each of said cables may be introduced into said cavity in an insulated manner and exposed therein for electrical connection with an inner line of another of said cables; a plurality of pin-like elements insulated from the housing and including a first element connected electrically to the inner line of the first cable, and a second and third element connected electrically to the inner line of the second and third cables respectively, one end of each of said elements serving as a contact point and providing at least partial shielding for the exposed inner line of each of said cables and each of said elements connected thereto from the inner line of each of the other of said cables and the elements connected respectively thereto; a pair of conductive reeds, at least one of said reeds being of magnetizable material, one of said reeds being disposed to bridge and electrically connect the contact points of the first element and the second element, and the other of said reeds being disposed to bridge and electrically connect the contact points of the first element and the third element; means for disposing each of said conductive reeds so that it may be displaced from a first position in which it bridges and electrically connects the two contact points which it is so adapted to bridge and electrically connect, to a second position in which it is out of contact with both of said contact points and is grounded against the wall of the metallic housing; electromagnetic means, responsive to an input signal for creating a magnetic field embracing the magnetizable reed to displace it from its first position to its second position; a rocker arm assembly, said assembly including an arm and a fulcrum disposed intermediate the extremities of the arm and about which fulcrum the arm pivots, said assembly being so disposed that one end of said arm is mechanically attached to the other reed, whereby when said arm is disposed in a first position, the magnetizable reed attached to one end thereof is disposed in its first position and the other reed attached to the other end of the arm is disposed in its second position, and conversely, when said arm is rocked from its first position into a second position; spring means associated with at least one end of said arm and urging it against movement into its second position, said spring means, however, providing an insufficient urging force to prevent the magnetizable reed from being displaced to its second position by the energization of said electromagnetic means; and an electrical switch, said switch being connected selectively to apply voltage from said voltage source to said electromagnetic means to energize the same.
 19. The switching means as described in claim 18 including an indicator circuit comprising: indicating means visible outside the housing to disclose whether said rocker arm is disposed in its first or second position, an actuating arm connected to the indicating means and movable with the rocker arm to actuate the indicating means in accordance with the positioning of said arm.
 20. The switching means as described in claim 18, wherein before either reed is moved into its first position, the other reed is first removed from its first position, thereby providing a ''''break-before-make'''' switching action.
 21. The switching means described in claim 18, wherein the cavity in the metallic housing is covered by a sheet of electrically conductive tape having an adhesive surface, which surface is pressed into contact with the top of the housing walls defining the cavity. 